1. Field of the Invention
This invention pertains to domes for the enclosure o vast areas suitable for human working and dwelling. More specifically, domes having a minimum radius of one-half mile are provided with horizontal ribs about the exterior surface. These ribs lessen the dome's lift and drag coefficients thus reducing the wind forces that must be borne by the structure. Domes so constructed could be used to enclose self supporting land or sea based cites with dwellings, businesses and factories, parks and nature areas as well as agriculture and aquaculture. Although a purpose-designed domed city could be truly three dimensional, domes could also be placed over existing cities.
2. Background of the Prior Art
Mankind has envisioned the provision of dome-enclosed life supporting habitats for many years ranging from futuristic Science Fiction to serious engineering symposia. For example, domes enclosures for cites of distant planetary bodies have long been conceptualized as a method of protecting colonists from a hostile environment until the colonized world can be "terraformed." Additionally, the concept of floating cities was explored at the 1971 symposium of the International Association for Shell Structures with published proceedings (Pacific Symposium Part I, ed. Rudolph Szilard).
A need for large enclosed areas may also exist for more down to earth, land based applications. Curtis Charles has recently proposed that Trinidad and other equatorial countries build dome enclosed, combined hydroponic agriculture and aquaculture facilities that utilize natural light to help their agricultural and fishing industries (Technology Review, Vol. 93, Nol. 5, June 1990, p. MIT 36). Similarly, hostile polar locations or areas suffering drastic climactic changes, such as due to possible effects of global warming, could be made habitable by employing suitable, domed enclosures.
Accounting for loads on the structure is of primary importance in designing such very large domes, that is, domes having a radius of at least one half mile. The three largest loading factors are material weight loads; passive moisture loads including snow, ice, rain and condensation; and wind loads.
Loads from the dome materials themselves are substantial in domes of the size here considered, but they are constant and therefore predictable and can be accounted for. Passive moisture loads are less predictable but vary relatively slowly and thus may be accommodated by assuming some upper bound on their magnitude. The most problematic loads are those induced by the wind. Wind loads can vary rapidly and nonuniformly and are thus difficult to account for. Their effects can be further amplified when coupled with snow, rain, or hail. But the air flow about the dome can be controlled, to some extent, in the dome design thereby minimizing the effects of impacting winds. In particular, the lift and drag coefficients may be reduced to lessen the associated lift and drag forces on the dome. Further, deflectors may be situated about the dome so as to diminish the effects of projectiles associated with the wind.